Vinyl resin plasticized with an adduct of an alkyl vinylphosphonate



United States The present invention relates to polyphosphonates, methodsof producing the same and to resinous compositions comprising vinylchloride polymers plasticized with the polyphosphonates.

According to the invention there are provided new and highly valuableliquid mixtures of pclyphosphonates by the free-radical-catalyzedaddition of a vinylphosphonate with a solvent for said phosphonate,Whichsolvent is selected from the class consisting of alkyl anddialkylbenzenes having from 1 to 3 carbon atoms in the alkyl radical,normally liquid dialkyl phosphites having from 1 to 8 carbons atoms inthe alkyl radical, and halogenated alkanes having from 1 to 2 carbonsatoms. and containing at least 3 halogen atoms attached to the samecarbon atom. The reaction is one of simple addition in which one mole ofsaid solvent adds to from 2 to 50 moles of the-vinylphosphonate. Thepresent polyphosphonates are thus adducts of the formula in which R andR are alkyl radicals of from 1 to 8 carbon atoms, and n is an integer offrom 2 to 50 and S is the herein defined solvent. Examples of thedialkyl vinylphosphonates are din'rethyl, diethyl, diisopropyl,di-n-butyl, di-tert-butyl, di-

n-amyl, di-n-hexyl, di-n-octyl, bis(2-ethylhexyl) vinyl-.

phosphonates or the mixed esters such as ethyl methyl or. isobutyln-propyl vinylphosphonate. A mixture of different dialkylvinylphosphonates may be employed to give" adducts having differentrecurring alkyl radicals. As illustrative of the alkylbenzene ordialkylbenzene type solvents which add to from 2 to 50 molesof thevinylphosphonates according to the invention may. be mentioned toluene,m-and p-xylene,-.'ethylbenzene, 0-, mand p-diethylbenzene, 0-,, mand,p-ethyltoluene, cumene, 0-, mand p-dipropylbenzene, p-cymene, 0-, mandp-ethylcum'ene, etc. Such alkylbenzenes possess at least one alkylradical having a labile hydrogen atom and react readily with thevinylphosphonates' to give the normally liquid polyphosphonates.

Examples of the halomethane type solvents which add to thevinylphosphonatesto give the present normally liquid polyphosphonatesare carbon tetrachloride, carbon tetrabromide, chloroform, bromoform,bromotrichloromethane, chlorotribromoethane, difluorodichlorornethane,iodoform, hexachloroethane, asym-tetrabromoethane,dibromotetrachloroethane, etc.

Examples of the dialkyl phosphite type of solvents are the dimethyl,diethyl, di-n-propyl, di-n-butyl, diisobutyl, di-n-amyl, ethyl methyl orn-butyl isopropyl phosphites.

Free-radical-liberating agents which may be employed in promotingaddition of the present vinylphosphonate to the solvent are compoundswhichwill decompose to give free radicals. Such compounds includeperoxygen type catalysts, for example,-acylperoxides such as acetyl,ben-.

3,022,261 Patented Feb. 20, 1962 ide or Z-cymene hydroperoxide; andinorganic per compounds such as hydrogen peroxide, sodium peroxide,sodium perborate, potassium persulfate, and alkali percarbonate;hydrazine derivatives such as hydrazine hydrochloride and dibenzoylhydrazine; organo-metallic compounds such as tetraethyl lead, etc. Forconvenience,- the peroxygen type catalysts will be hereinafter referredto as peroxidic compounds, Only catalytic quantities of thefree-radical-liberating agent need be employed in promoting the additionreaction. Ultra-violet light may be employed with the catalyst or as thesole catalytic agent.

Formation of the present adducts probably proceeds through-a chainmechanism, with termination of the polyvinylphosphonate chain at anearly stage, i.e., at a point at which no more than 50 moles of thevinylphosphonate have added to one mole of the solvent. Depending uponthe nature and the quantity of the reactants and of thefree-radical-liberating 'agent, as well as upon the reaction conditions,chain propagation may be terminated at various stages to yield productsin which from 2 to 5O moles of-the vinylphosphonate have added to onemole of the solvent. Atany stage, however, mixtures of a series of thepolyphosphonate adducts are obtained. Each adduct; contains only onemole of the solvent, but the number of moles of vinylphosphonate presentin each adduct may be from 2 to 50 and the proportion of the variousadducts in the reaction mixture may be such as to give an average of,say, up to 5 moles or up to 20 moles, or even up to 45 moles of thevinylphosphonate per mole of the solvent. The individual adducts presentin the mixture may be separated from each other only with difiiculty;for most purposes the liquid mixtures of adducts are employed directlyas they have been formed; or there are employed mixtures'having a narrowrangev of molecular weights, which mixtures are easily obtainable byfractional distillation of the reaction product or by termination of.the reaction at predetermined stages.

In preparing the present polyphosphonate adducts we generally operate asfollows: The vinylphosphonate is mixed with the' solvent and thefree-radical-librating catalyst and the resulting mixture is maintained,advantageously with agitation, at a temperature which permits asteadydecomposition of the catalyst and consequent steady liberation offree radicals from the solvent, Or,-if desired, the ester may be, addedgradually, e.g.,

. dropwise, to the solvent while constantly vmaintaining.an

optimum quantity of active catalyst in the', reaction zone, which zoneis preferably kept at a temperature which is. conducive to the formationoffree'. radicals. Depending upon the nature of the individual reactantsandcatalystand the properties desired in the final product. increasedtemperatures, e.g., temperatures-of, say, from C. to about 125 C. may begenerally employed. The reaction time may vary from, say, several hoursto several days. Substantially equimolar quantities of the solvent andthe vinylphosphonate may be used; however, for the production, in goodyields, of adducts in which from 2 to 50 moles of the phosphonate havecombined with one mole of solvent, an excess of the solvent ispreferred. An excess of the vinylphosphonate is not recommended.

, Variation of catalyst quantity has been found to have The use of lowerquantities of catalyst tends to favor formation of the. highermolecular-weight adducts.

The progress of the additionreaction may bev readily gauged by notingchange in viscosity of the reaction mixture. When a liquid product ofthe desired viscosity has been attained, or when there -is cessationin.,.viscositychange, the reaction mixture may be distilled to removeunreacted solvent and/or vinylphosphonate and catalyst. The residue willcomprise a mixture of the polyphosphonate adducts.

In preparing the present adducts there may be em ployed, in addition tothe present chain-terminating solvents, an inert diluent or unreactivesolvent. For example, benzene or hexane may be used together with thealkylbenzene, alkyl phosphite or haloalltane, either to serve ascatalyst solvent, to mitigate reaction heat, or to dilute theconcentration of the vinylphosphonate in the reaction mixture. The useof such a solvent or diluent, however, is of little economic advantage.

The present polyphosphonate adducts are clear, easily flowing liquidswhich are characterized by very good stability to heat and light. Theymay be advantageously used for a variety of industrial and agriculturalpurposes, for example, as dielectric or other functional fluids, aslubricant additives, and as biological toxicants. The present adductsgenerally confer plasticity to resinous polymeric materials. They areparticularly valuable as plasticizers for vinyl chloride polymers, andfor the polyvinyl acetals, e.g., the polyvinyl butyral known to thetrade as Butvar, with which polymers they may be employed with advantageeither as sole or as secondary plasticizers.

The present adducts impart flexibility to vinyl chloride polymers at lowtemperatures; they are compatible with said polymers, and show noexudation of plasticizer even at plasticizcr content of up to 60%.Although the quantity of plasticizer will depend upon the particularpolymer to be plasticized and upon its molecular Weight, it is generallyfound that compositions having from to 60% by weight of plasticizerwill, in most cases, be satisfactory for general utility. The goodflexibility of the present plasticized composition increases withincreasing plasticizer concentration. I

It is advantageous with some of the present vinylphosphonate adducts toemploy increased temperatures in blending them with the vinyl chloridepolymers. Temperatures of from, say, 200 F. to 350 F. may beadvantageously employed in effecting a homogeneous blend of the vinylchloride polymer and the adducts. The present adducts are particularlyvaluable when employed in conjunction with known polyvinyl chlorideplasticizers, for example, especially those of the alkyl aryl phosphateclass.

In evaluating plasticizer eificiency use is made of the followingempirical testing procedures:

Compatibility.-Visual inspection of the plasticized composition isemployed, incompatibility of the plasticizer with the polymer beingdemonstrated by cloudiness and exudation of the plasticizer.

' Low temperature flexibility.Low temperature flexibility is one of themost important properties of elastomeric vinyl compositions. While manyplasticizers will produce flexible compositions at room temperature theflexibility of these compositions at low temperatures may varyconsiderably, i.e., plasticized polyvinyl chloride compositions that areflexible at room temperature often become very brittle and useless. atlow temperatures. Low temperature flexibility tests herein employed areaccording to the Clash-Berg method. This test is a measure of thestiifness of a plastic specimen as a function of temperature, measuredby a means of a torsional test. The test is essentially as described byClash and Berg, Industrial and Engineering Chemistry, 34 1218 (1942).

Mechanical properties.--Tensile strength and percent elongation weredetermined by the standard test of the American Society for TestingMaterials D-638-52T and D-4I2-41.

The invention is further illustrated, but not limited, by the followingexamples:

Example 1 A mixture consisting of 35 g. of di-n-butyl vinylphosphonate,1.75 g. (5% by weight) of benzoyl peroxide and 138 g. of carbontetrachloride was charged to a stoppered bottle, and then maintained,with agitation, in a circulating air oven at 95 C. for 19 hours. Theresulting reaction mixture was distilled to remove material boiling upto 175 C./l2 mm. Hg pressure, and there was thus obtained as residue 43g. of the light yellow liquid adduct of carbon tetrachloride anddi-n-butyl vinylphosphonate, 21 1.4738. It was readily soluble inbenzene and was soluble in. lubricating oil up to at least 3%. Chlorineanalysis of the adduct gave a value of 16.62%, which indicatescombination of one mole of the carbon tetrachloride with an average of3.18 moles of the di-n-butyl vinylphosphonate.

Example 2 There was milled to a homogeneous blend a mixture consistingof 30 parts by weight of the adduct of Exampie 1, 70 parts by weight ofpolyvinylchloride and 2 parts by Weight of a stabilizer known to thetrade as Thermolite 31" said stabilizer is an organo tin derivative of amercapto carboxy compound prepared as described in the Weinberg et al.US. Patent No. 2,648,650. Molded test specimens prepared therefromcompare as follows with respect to tensile strength and elongation to asimilarly prepared specimen from 28 parts by weight of dioctyl phthalateand 72 parts by weight of the polyvinyl chloride or to the unplasticizedpolyvinyl chloride:

Plesticlzer None . Adduct of Dioctyl Ex. 1 phthalato Tensile strength atfailure, p.s.i 6, 841 5, 200 2,827 Elongation at failure, percent 50 205228 In another test, films were cast from a cyclohexanone solution of amixture consisting of 30 parts by weight of the di-n-butyl ethylenephosphonate-carbon tetrachloride adduct and 70 parts by weight ofpolyvinyl chloride. The films were dried at 100 C., cooled and thenstripped. Microscopic examination of the clear and flexible film thusobtained revealed no incompatibility of the telomer with the polyvinylchloride.

Example 3 A mixture consisting of 245 g. of di-n-butyl vinylphosphonate,12.25 g. of benzoyl peroxide and 966 g. of carbon tetrachloride wascharged to seven bottles, the bottles were capped and then maintainedona rocking rack in an oven at 95 C. for 72 hours. Subsequentdistillation of the combined reaction mixtures to remove materialboiling up to C./l2 mm. Hg pressure gave as residue 284 g. of a clearliquid residue, 11 1.4762, and having a specific gravity of 1.169.Analysis of this residue gave 16.16% chlorine, thus indicating it to bean adduct in which one mole of the carbon tetrachloride is combined withan average of 3.29 moles of the di-n-butyl vinylphosphonate.

Example 4 This example shows evaluation of the adduct. of Example 3 as asecondary plasticizer with a commercial, alkyl aryl phosphate typeplasticizer known to the trade as Santicizer 141. The followingformulations were 5 The above mixtures were respectively'blended on themill at roll temperatures of 340 F., and molded test specimens wereprepared from the milled sheets at a molding pressure of 100 p.s.i.Testing of the specimens by the procedures described above gave thefollowing 1 values:

Class-Berg Tensile Percent Formulation strength elongation at break 1 atbreak Ir touo' I -25. 22. 8 3, 990 328 II -27. 12. 0 2, 410 354 1 Usinga cross-head speed of 20'lmin.

Example 5 A mixture consisting of 35 g. (0.159 mole) of di-nbutylvinylphosphonate, 105 g. (0.477 mole) of di-n-butyl hydrogen phosphiteand 1.75 g. of benzoyl peroxide was maintained, with agitation, at atemperature of 95 C. for 72 hours. Removal of unreacted material andstripping of the pot residue to a temperature of 200 C./ 1-2 mm. gave asresidue 47 g. of the viscous, liquid adduct of di-n-butylvinylphosphonate and di-n-butyl hydrogen phosphite, analyzing 13.17%phosphorus.

Example 6 The di-n-butyl vinylphosphonate-di-n-butyl hydrogen phosphiteadduct of Example 5 was tested as a plasticizer for polyvinyl chlorideusing the following formulations:

Parts by Percent by weight volume I. Polyvinyl chloride 35. 7 60 Adductof Example 5 20. 0 40 Stabilizer RS31 1. 0 II Polyvinyl chloride. 53. 560 Adduct of Example 5.- 15.0 20 Santicizer 141 14. 0 20 StabilizerRS-31 1. 0

The stabilizerused above is reputed to be anorganic compound of tin. TheSanticizer 141 is a commercial plasticizer of the alkyl aryl phosphatetype.

Formulations l and II were respectively milled on rolls at full steam(340 F.). Two different molding procedures were used, i.e., molding waseffected in one case at a pressure of 200 p.s.i. and in the other at apressure of 1,000 p.s.i. The following Clash-Berg and tensile valueswere obtained:

A mixture consisting of 35 g. of diethyl vinylphosphonate, 138.3 g. ofcarbon tetrachloride and 1.75 g. of benzoyl peroxide was maintained,with agitation, at a temperature of 95 C. for 70 hours. The resultingreaction mixture was distilled to remove carbon tetrachloride and theviscous residue thus obtained was held at 160-170 C./2-3 mm. for 1 hour.There was thus obtained as residue 37 g. of the amber syrupy diethylvinylphosphonate-carbon tetrachloride adduct which was soluble in waterwith accompanying hydrolysis.

6 Example 8 This example shows preparation of an adduct of di-nbutylvinylphosphonate and p-cymene. A mixture consisting of 25 g. of'thephosphonate, 100 g. of the cymene and 0.633 ml. of di-tert-butylperoxide was maintained, with agitation, in a circulating air oven at atemperature of 120 C. for 72 hours. Distillation of the resultingreaction mixture to remove material boiling below 185 C./1 mm. gave asresidue 21.4 g. (81.5% yield) of the viscous di-n-butylvinylphosphonate-p-cymene adduct analyzing 58.37% carbon as against54.9%,, the carbon value formonomeric di-n-butyl vinylphosphonate. Amolded test specimen prepared from 100 parts by weight of polyvinylchloride and 42.9 parts by weight of the'present adduct was clear andtransparent. Employing a cross-head speed of 2"/rnin. it was found tohave a tensile strength at break of 4130 p.s.i. and an elongation atbreak of 235%.

Example 9 This example is like Example 8 except that instead of usingp-cymene, diisopropylbenzene was employed. The viscous residue obtainedupon removing material B1. below 185 C./1 mm. analyzed 57.98% carbon,indicating the presence of an adduct of the diisopropylbenzene and a lowmolecular weight polymeric di-n-butyl vinylphosphonate. A molded testspecimen prepared from 100 parts by weight of polyvinyl chloride and42.9 parts by weight of the present adduct was clear and transparent.Using a cross-head speed of 2"/min, it was found to have a tensilestrength at break of 2130 p.s.i. and a percent elongation at break of235.

Example 10 The carbon tetrachloride-di-n-butyl vinylphosphonate adductof Example 3 was further tested as a plasticizer for a polyvinyl butyralresin known to the trade as Butvar. A mixture consisting of 44 parts byweight of the adduct and 66 parts by weight of the Butvar was dissolvedin a solvent consisting of 95 parts by weight of the tetrahydrofuran.Films cast from the resulting solution were dried, cooled and stripped.Microscopic examination of the flexible transparent and colorless filmthus obtained showed complete compatibility of the adduct.

This application is a division of my copending application Serial No.439,486, filed June 25, 1954, and now Patent No. 2,844,618, issued July22, 1958.

What we claim is:

1. A resinous composition comprising a polymer selected from the classconsisting of polyvinyl chloride and a. polyvinyl acetal plasticizedwith an adduct in which there are chemically combined from 2 to 50 molesof an alkyl vinylphosphonate in which the alkyl radical has from 1 to 8carbon atoms with 1 mole of a compound which is a solvent for saidphosphonate and which is selected from the class consisting of alkyl anddialkyl benzenes having from 1 to 3 carbon atoms in the alkyl radical,normally liquid alkyl phosphites having from 1 to 8 carbon atoms in thealkyl radical and halogenated alkanes having from 1 to 2 carbon atomsand contain ing at least 3 halogen atoms attached to the same carbonatom.

2. A resinous composition comprising polyvinyl chloride plasticized withan adduct in which there are chemically combined 1 mole of a dialkylphosphite having from 1 to 8 carbon atoms in the alkyl radical with from2 to 50 moles of an alkyl vinylphosphonate having from 1 to 8 carbonatoms in the alkyl radical.

3. A resinous composition comprising polyvinyl chloride plasticized withan adduct in which there are chemically combined 1 mole of halogenatedalkane having from 1 to 2 carbon atoms and containing at least 3 halogenatoms with from 2 to 50 moles of an alkyl aoaaaer vinylphosphonatehaving from 1 to 8 carbon atoms in the alkyl radical. s

4. A resinous composition comprising polyvinyl chloride plasticized withan adduct in which there are chemically combined 1 mole of carbontetrachloride with from 2 to 50 moles of di-n-butyl vinylphosphonate.

5. A resinous composition comprising polyvinyl chloride plasticizeclwith an adduct in which there are chemically combined 1 mole ofdi-n-butyl hydrogen phosphite with from 2 to 50 moles of di-n-butylvinylphosphonate.

6. A resinous composition comprising polyvinyl chloride plasticized withan adduct in which there are chemically combined from 2 to 50 moles ofan alkyl vinylphosphonate in which the alkyl radical has from 1 to 8carbon atoms with 1 mole of a compound which is a solvent for saidphosphonate and which is selected from the class consisting of alkyl anddialkyl benzenes having from 1 to 3 carbon atoms in the alkyl radical,normally liquid alkyl phosphites having from 1 to 8 carbon atoms in thealkyl radical and halogenated alkanes having from 8 1 to 2 carbon atomsand containing at least 3 halogen atoms attached to the same carbonatom.

7. A resinous composition comprising a polyvinyl acetal plasticized withan adduct in which there are chemically combined from 2 to 50 moles ofan alkyl vinylphosphonate in which the alkyl radical has from 1 to 8carbon atoms with 1 mole of a compound which.

is a solvent for said phosphonate and which is selected from the classconsisting of alkyl and dialkyl benzenes having from 1 to 3 carbon atomsin the alkyl radical, normally liquid alkyl phosphites having from 1 to8 carbon atoms in the alkyl radical and halogenated alkanes having from1 to 2 carbon atoms and containing at least 3 halogen atoms attached tothe same carbon atom.

8. A resinous composition comprising polyvinyl butyral plasticized withan adduct in which there are chemically combined one mole of carbontetrachloride with from 2 to 50 moles of di-n-butyl vinylphosphonate.

No references cited.

1. A RESINOUS COMPOSITION COMPRISING A POLYMER SELECTED FROM THE CLASSCONSISTING OF POLYVINYL CHLORIDE AND A POLYVINYL ACETAL PLASTICIZED WITHAN ADDUCT IN WHICH THERE ARE CHEMICALLY COMBINED FROM 2 TO 50 MOLES OFAN ALKYL VINYLPHOSPHONATE IN WHICH THE ALKYL RADICAL HAS FROM 1 TO 8CARBON ATOMS WITH 1 MOLE OF A COMPOUND WHICH IS A SOLVENT FOR SAIDPHOSPHONATE AND WHICH IS SELECTED FROM THE CLASS CONSISING OFALKYL ANDDIALKYL BENZENES HAVING FROM 1 TO 3 CARBON ATOMS IN THE ALKYL RADICAL,NORMALLY LIQUID ALKYL PHOSHITES HAVING FROM 1 TO 8 CARBON ATOMS IN THEALKYL RADICAL AND HALOGENATED ALKANES HAVING FROM 1 TO 2 CARBON ATOMSAND CONTAINING AT LEAST 3 HALOGEN ATOMS ATTACHED TO THE SAME CARBONATOM.